Detectionhightest

Suspicious Command Patterns In Scheduled Task Creation

Detects scheduled task creation using "schtasks" that contain potentially suspicious or uncommon commands

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Florian Roth (Nextron Systems)Created Wed Feb 23Updated Tue Mar 19f2c64357-b1d2-41b7-849f-34d2682c0fadwindows

Log Source

WindowsProcess Creation

ProductWindows← raw: windows

CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic

detection:
    selection_schtasks:
        Image|endswith: '\schtasks.exe'
        CommandLine|contains: '/Create '
    selection_pattern_1:
        CommandLine|contains:
            - '/sc minute '
            - '/ru system '
    selection_pattern_2:
        CommandLine|contains:
            - 'cmd /c'
            - 'cmd /k'
            - 'cmd /r'
            - 'cmd.exe /c '
            - 'cmd.exe /k '
            - 'cmd.exe /r '
    selection_uncommon:
        CommandLine|contains:
            - ' -decode '
            - ' -enc '
            - ' -w hidden '
            - ' bypass '
            - ' IEX'
            - '.DownloadData'
            - '.DownloadFile'
            - '.DownloadString'
            - '/c start /min ' # https://twitter.com/RedDrip7/status/1506480588827467785
            - 'FromBase64String'
            - 'mshta http'
            - 'mshta.exe http'
    selection_anomaly_1:
        CommandLine|contains:
            - ':\ProgramData\'
            - ':\Temp\'
            - ':\Tmp\'
            - ':\Users\Public\'
            - ':\Windows\Temp\'
            - '\AppData\'
            - '%AppData%'
            - '%Temp%'
            - '%tmp%'
    selection_anomaly_2:
        CommandLine|contains:
            - 'cscript'
            - 'curl'
            - 'wscript'
    condition: selection_schtasks and ( all of selection_pattern_* or selection_uncommon or all of selection_anomaly_* )